[alsa-devel] [PATCH v5] ASoC: omap-mcbsp: Add PM QoS support for McBSP to prevent glitches

[Tony Lindgren]

* Matt Ranostay <matt at ranostay.consulting> [170109 14:11]:
> On Mon, Jan 9, 2017 at 1:56 PM, Tony Lindgren <tony at atomide.com> wrote:
> > * Matt Ranostay <matt at ranostay.consulting> [170109 13:46]:
> >> On Mon, Jan 9, 2017 at 11:21 AM, Tony Lindgren <tony at atomide.com> wrote:
> >> > * Peter Ujfalusi <peter.ujfalusi at ti.com> [170109 05:13]:
> >> >> On 01/05/2017 03:59 AM, Matt Ranostay wrote:
> >> >> > We can get audio errors if hitting deeper idle states on omaps:
> >> >> >
> >> >> > [alsa.c:230] error: Fatal problem with alsa output, error -5.
> >> >> > [audio.c:614] error: Error in writing audio (Input/output error?)!
> >> >> >
> >> >> > This seems to happen with off mode idle enabled as power for the
> >> >> > whole SoC may get cut off between filling the McBSP fifo using DMA.
> >> >> > While active DMA blocks deeper idle states in hardware, McBSP
> >> >> > activity does not seem to do so.
> >> >> >
> >> >> > Basing the QoS latency calculation on the FIFO size, threshold,
> >> >> > sample rate, and channels.
> >> >>
> >> >> Looks good to me, thank you!
> >> >>
> >> >> Acked-by: Peter Ujfalusi <peter.ujfalusi at ti.com>
> >> >
> >> > Noticed the following about 10 seconds into playing an mp3 file with
> >> > mpg123 though:
> >> >
> >>
> >> Didn't notice that happening for me. But haven't rebased for the last
> >> couple days.
> >> Does this happen 100% of the time?
> >
> > Yeah seems to based on three attempts. This with 4.10.0-rc2-next-20170109.
> >
> 
> Ok I'll test this myself this evening and report back.

Oh and this is with omap2plus_defconfig with the following also enabled:

CONFIG_DEBUG_LOCKDEP=y
CONFIG_DEBUG_ATOMIC_SLEEP=y

Tony